First Application of Newly Developed FT-NIR Spectroscopic Methodology to Predict Authenticity of Extra Virgin Olive Oil Retail Products in the USA

Economically motivated adulteration (EMA) of extra virgin olive oils (EVOO) has been a worldwide problem and a concern for government regulators for a long time. The US Food and Drug Administration (FDA) is mandated to protect the US public against intentional adulteration of foods and has jurisdiction over deceptive label declarations. To detect EMA of olive oil and address food safety vulnerabilities, we used a previously developed rapid screening methodology to authenticate EVOO. For the first time, a recently developed FT-NIR spectroscopic methodology in conjunction with partial least squares analysis was applied to commercial products labeled EVOO purchased in College Park, MD, USA to rapidly predict whether they are authentic, potentially mixed with refined olive oil (RO) or other vegetable oil(s), or are of lower quality. Of the 88 commercial products labeled EVOO that were assessed according to published specified ranges, 33 (37.5%) satisfied the three published FT-NIR requirements identified for authentic EVOO products which included the purity test. This test was based on limits established for the contents of three potential adulterants, oils high in linoleic acid (OH-LNA), oils high in oleic acid (OH-OLA), palm olein (PO), and/or RO. The remaining 55 samples (62.5%) did not meet one or more of the criteria established for authentic EVOO. The breakdown of the 55 products was EVOO potentially mixed with OH-LNA (25.5%), OH-OLA (10.9%), PO (5.4%), RO (25.5%), or a combination of any of these four (32.7%). If assessments had been based strictly on whether the fatty acid composition was within the established ranges set by the International Olive Council (IOC), less than 10% would have been identified as non-EVOO. These findings are significant not only because they were consistent with previously published data based on the results of two sensory panels that were accredited by IOC but more importantly each measurement/analysis was accomplished in less than 5 min.     

Evaluating the In Vitro Metabolism of Docosahexaenoic Acid in Sheep Rumen Fluid

Rumen metabolism (e.g., biohydrogenation) of dietary unsaturated fatty acids (FA) is one of the main reasons why ruminant fats tend to be highly saturated and contain many isomerized FA intermediates. The process by which long-chain (20- to 24-carbon FA) polyunsaturated FA (LC-PUFA) are metabolized by rumen bacteria is not as well understood as that of linoleic or linolenic acids. In order to better understand the fate of LC-PUFA in the rumen several concentrations of docosahexaenoic acid (DHA) were evaluated in in vitro batch incubations ranging from 100 to 1,500 μg per 6 mL of incubation volume using rumen fluid from sheep and incubated for 0, 1, 2, 3, and 6 h. From the results, it was shown that DHA was extensively metabolized at low (100 to 300 μg/6 mL incubation volume), but not at high level of inclusion (800 μg). At 300 μg of DHA most of the depleted DHA was recovered as LC-DHA metabolites within the first 6 h of incubation, and at the lowest levels (100 μg of incubation volume) further metabolism is apparent at 6 h. Using SP-2560 GC columns several LC-DHA metabolites were shown to elute after 24:0 and just past DHA, a region generally free of interfering FA. The present in vitro study would appear to be a useful method to evaluate the production of DHA metabolites in combination with its depletion.     

Comparison of Separations of Fatty Acids from Fish Products Using a 30-m Supelcowax-10 and a 100-m SP-2560 Column

Commercial fish oils and foods containing fish may contain trans and/or isomerized fatty acids (FA) produced during processing or as part of prepared foods. The current American Oil Chemists’ Society (AOCS) official method for marine oils (method Ce 1i-07) is based on separation by use of poly(ethylene glycol) (PEG) columns, for example Supelcowax-10 or equivalent, which do not resolve most unsaturated FA geometric isomers. Highly polar 100-m cyanopropyl siloxane (CPS) columns, for example SP-2560 and CP Sil 88 are recommended for separation of geometric FA isomers. Complementary separations were achieved by use of two different elution temperature programs with the same CPS column. This study is the first direct comparison of the separations achieved by use of 30-m Supelcowax-10 and 100-m SP-2560 columns for fatty acid methyl esters (FAME) prepared from the same fish oil and fish muscle sample. To simplify the identification of the FA in these fish samples, FA were fractionated on the basis of the number and type of double bonds by silver-ion solid-phase extraction (Ag⁺-SPE) before GC analysis. The results showed that a combination of the three GC separations was necessary to resolve and identify most of the unsaturated FA, FA isomers, and other components of fish products, for example phytanic and phytenic acids. Equivalent chain length (ECL) values of most FAME in fish were calculated from the separations achieved by use of both GC columns; the values obtained were shown to be consistent with previously reported values for the Supelcowax-10 column. ECL values were also calculated for the FA separated on the SP-2560 column. The calculated ECL values were equally valid under isothermal and temperature-programmed elution GC conditions, and were valuable for confirmation of the identity of several unsaturated FAME in the fish samples. When analyzing commercially prepared fish foods, deodorized marine oils, or foods fortified with marine oils it is strongly recommended that quantitative data acquired by use of PEG columns is complemented with data obtained from separations using highly polar CPS columns.     

Friction coefficients in cold forging: A global perspective

Worldwide, at least twenty different tribological tests have been proposed for the empirical determination of friction coefficients in cold forging processes. Due to the varying test setups, means of measurement, and level of abstraction, the comparability of the outcomes is, however, disputable. Within this work, six established test principles are compared using identical tribological systems. Large differences between the empirically determined friction coefficients are observed but can be explained under consideration of the respective tribological loads. Additional investigations of an extrusion process reveal that friction models also have to take into account the varying local thickness of the lubricant film.     

Application of generic principles of process intensification to solution crystallization enabled by a task-based design approach

The design of current industrial crystallizers is strongly focussed on optimization of known types of crystallization equipment. These crystallizers harbour various physical phenomena, which are strongly entangled. The application of generic principles of process intensification (PI) to crystallization processes requires individual control over physical phenomena. A new design method is applied that exploits elementary processing functions as building blocks for design instead of existing equipment, which enables the application of generic principles of PI. Innovations in the field of crystallization to manipulate shear forces, manipulate nucleation rates with external fields, and improve control over solvent removal with membranes are key technologies. A case study demonstrates the application of task-based design for solution crystallization. The results show how task-based design leads to high modularization of the process representation and model architecture. In addition, task-based design enables the application of generic PI principles, which results in a large flexibility to manipulate final product quality. Future needs include generalization of task-based design for crystallization and development of novel technologies for single task manipulation.     

Determination of the eutectic solubility lines of the ternary system NaHCO3–Na2CO3–H2O

A crystallizer was built and a procedure developed to accurately measure the eutectic solubility lines where ice and salt coexist in equilibrium with the solution, for potential application of Eutectic Freeze Crystallization. The eutectic solubility lines of the ternary system NaHCO₃–Na₂CO₃–H₂O were determined experimentally and calculated with the extended UNIQUAC model. The extended UNIQUAC model describes the experimental data quite well. Anhydrous NaHCO₃ and Na₂CO₃·10H₂O were the only two types of crystals present in equilibrium with ice crystals in the ternary system. At the quadruple point NaHCO₃ and Na₂CO₃·10H₂O are in equilibrium with a solution of about 4.34 wt% of Na₂CO₃ and 4.77 wt% of NaHCO₃ at −3.32 °C. The anhydrous NaHCO₃ crystals were needle shaped with lengths between 5 and 10 μm, that were agglomerated into particles of about 100–300 μm, while the Na₂CO₃·10H₂O crystals were hexagonally shaped with sizes between 100 and 500 μm.     

Formation of quasicrystals in Zr–Pd–(Cu) melt spun ribbons and mechanically milled powders

Amorphous Zr₇₀Pd₃₀ and Zr₇₀Pd₂₀Cu₁₀ alloys were prepared by mechanical milling and melt spinnng to compare their devitrification behaviors. The devitrification of mechanically milled Zr₇₀Pd₃₀ and Zr₇₀Pd₂₀Cu₁₀ powders occurs via a single-step, first-order transformation to a stable Zr₂Pd tetragonal structure. This is in sharp contrast to the devitrification of the same amorphous alloys prepared by melt spinning, in which a primary meta-stable quasicrystalline phase forms. Since the mechanical milling process does not involve direct liquid phase formation of an amorphous structure, it is inferred that the short-range order in the solid state derived amorphous powder is different from that in the melt spun ribbon. During mechanical milling of an amorphous melt spun ribbon, crystallization of the quasicrystalline phase appears to precede disordering into an amorphous structure having an different short range order. Deformation of an amorphous melt spun ribbon by repetitive rolling at ambient temperature crystallizes the meta-stable quasicrystalline phase.